Method for adapting body support of a passenger seated in a vehicle seat in terms of vehicle movements dynamics and corresponding vehicle seat

ABSTRACT

A method for dynamic adaptation of the support, in particular the lateral support, of a person seated on a vehicle seat includes using an adaptation system, which is integrated in the vehicle seat, to determine the adaptation taking into account the current vehicle velocity. In order to compensate for the inherent inertia of the adaptation system, prediction of the adaptation is performed from stored data over the current road course, onto which data the current vehicle data are projected. The adaptation system is actuated taking into account the adaptation time inherent in the system in such a way that, when the event requiring the adaptation occurs, preferably when a bend is traveled through, at least one adaptation presetting is achieved.

The invention relates to a method for the dynamic adaptation of thesupport of the body, in particular the lateral support, of a personseated on a vehicle seat and a vehicle seat with adaptive body support,in particular lateral support.

A known vehicle seat (DE 35 41 537 A1) which is controlled dynamicallyhas inflatable air cushions for supporting the body of a person seatedon the seat. The cushions are integrated as shoulder supports in theupper part of the backrest, as a side support in the right-hand andleft-hand sides of the backrest, as a lumbar support, as a side supportof the seat cushion on the right and left and as right-hand andleft-hand supports for the thighs in the seat upholstery and in thebackrest upholstery. Each air cushion is connected to a valve unit. Thevalve units are actuated by a CPU (central processing unit). Sensors formeasuring the driving velocity of the vehicle, the lateral accelerationof the vehicle, the inclination of the vehicle and a rotational angle onthe steering wheel supply corresponding measurement data to the CPU,which themselves control the filling or venting of specific air cushionsvia the valve units as a function of the driving situation and thedriving style. In order to provide support when a lateral accelerationoccurs, such as when the vehicle turns, the CPU predicts the magnitudeof the lateral acceleration which will be exerted on the driver byreference to the instantaneous vehicle velocity and the rotational anglesupplied by the sensor on the steering wheel. The CPU then actuates thevalve devices for the air cushions to provide the lateral support, inthe seat upholstery and backrest upholstery such that the air cushionsare filled with a pressure which corresponds to the degree of predictedlateral acceleration.

A known method adapts the lateral support of a person seated on avehicle seat as a function of the driving situation and driving style(DE 197 50 223 A1). In this method, the lateral acceleration, which actson the seat, is measured with a lateral acceleration sensor and isdetermined as a reference variable for the adaptation of the lateralsupport of the seated person. In order to take the lateral accelerationsensation of the seated person into account to a greater degree, themeasured instantaneous lateral acceleration is weighted with themeasured instantaneous driving velocity of the vehicle, and a controlvariable for the degree of adaptation and/or the degree of lateralsupport is derived therefrom. This generates a more comfortable sittingsensation with the advantages of a necessary lateral holding which isbuilt up at short notice in bends.

A known vehicle velocity control device (DE 42 01 142 A1) has a vehiclenavigation system, for example GPS, which indicates the location of avehicle on a stored digital road map on a screen. The road map suppliesinformation on the road section on which the vehicle is travellingincluding bends in the road. The vehicle velocity control devicereceives the information on a bend lying ahead on a road, for example onthe radius of curvature of the bend, and calculates the vehicle limitingvelocity with which the vehicle can travel on the outside of the bendand travel safely through the bend. This vehicle limiting velocity iscompared with the instantaneous vehicle velocity. If the instantaneousvehicle velocity is higher than the limiting velocity, a warning is sentto the driver or velocity-reducing measures are automatically initiated.

The invention is based on the object of configuring a method of the typementioned at the beginning in such a way that the inertia of theadaptation system used to adapt the body support on the seat iscompensated.

This object is achieved according to the invention, as described below.

The method according to the invention has the advantage that a seatsetting for adapting the body support to an adaptation event, forexample travelling through a bend, is not carried out reactively onlywhen the adaptation event occurs. Rather the seat setting is carried outproactively so that it has already experienced the necessary change whenthe adaptation event starts. In this way, the delay, inherent in anyadaptation system, between the actuation of the adaptation system andthe changing of the seat is compensated. The method is thus no longerreliant on sensing and measuring driving manoeuvres which occur butrather adapts to the adaptation event even if the measurements havestill not supplied any clear results. The measured results are then onlyused to correct the seat setting which has been carried out, with onlyslight adjustment paths which can be overcome virtually without delay.By predicting the degree of necessary seat adaptation from the course ofthe road and the current vehicle data, the adaptation system can beconditioned with virtually any desired pre-travel and the support of thebody can gradually be adapted to the required degree in a way which isvirtually imperceptible to the seated person.

The invention is described below in more detail with reference to anexemplary embodiment illustrated in the drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a perspective view of a driver's seat for a passenger carwith the adaptation system illustrated in the block diagram andcontroller for the adaptation system.

DETAILED DESCRIPTION OF THE DRAWING

The driver's seat 10 for a passenger car illustrated in FIG. 1 as anexemplary embodiment of a generic car seat, has an upholstered seat part11 and an upholstered backrest 12 with headrest 13 projecting therefrom.An adaptation system 18 which is integrated into the vehicle seat 10permits the upholstered contours of the seat part 11 and backrest 12 tobe changed to support the body of a seated person in the driver's seat10 in an optimum fashion. The adaptation system 18 has been limited toproviding lateral support to the body, in particular when cornering. Forthis purpose, the adaptation system 18 has air cushions 14, 15 and 16,17 which are each integrated in the side bulges of the seat part 11 andbackrest 12. If the air cushions 14 to 17 are completely inflated, amaximum lateral support of the driver in the pelvic area and back areais achieved. The support can be reduced as the air pressure in the aircushions 14-17 is decreased. However, in addition to lateral support,shoulder support can also be provided in the upper part of the backrest,lumbar support can be provided in the lower region of the backrest andthigh support can be provided in the front region of the seat part 11.For this purpose, air cushions are also integrated into thecorresponding upholstery sections, as is described, for example, in DE35 41 537 A1.

In order to fill or vent the air cushions 14 to 17, the adaptationsystem 18 has a compressed air pump 20, a compressed air reservoir 21and a compressed air regulating device 22 which is connected thereto.The compressed air regulating device 22 comprises a pressure controller23 which switches the compressed air pump 20 on and off in order to keepa constant excess pressure at the input end, and a solenoid valve block24 which is capable of applying the input pressure specifically to, thefour air cushions 14 to 17. The pressure regulator which is integratedin the solenoid valve block 24 also provides the possibility of reducingthe pressure in the air cushions 14 to 17 by venting. The adaptationsystem 18 is controlled by a control unit 19 which has a central controlcomputer 25 which accesses the solenoid valve block 24 directly, andprocessing blocks 26 to 29 which are controlled by the control computer25. Two sensors 30 and 31 are connected to the control unit 19. Thesensor 30 measures the current vehicle velocity v, and the sensor 31measures the current lateral acceleration b acting on the vehicle seat.

A weighting algorithm, which describes the relationship between thevehicle velocity v and the lateral acceleration sensed by the driver, isstored in the block 26. The current lateral acceleration b istransformed into a sensed lateral acceleration with this algorithm. Thisallows for the phenomenon according to which the driver accepts a highdegree of lateral acceleration at a low velocity without desiringlateral support and considers a lateral support desirable at a highvelocity even for small lateral acceleration values to be taken intoaccount. A first characteristic curve, which predefines a relationshipbetween sensed lateral acceleration and a corresponding desired degreeof single-sided lateral support, is stored in block 27. The sensedlateral acceleration is determined from the currently measured lateralacceleration b and the currently measured vehicle velocity v in block26. A control variable, which is fed as an electrical signal from thecentral control computer 25 of the pressure regulating device 22 to thesolenoid valve block 24 for setting the output pressure is formed fromthe characteristic curve in block 27 using the sensed lateralacceleration.

The driving style of the vehicle driver is classified in block 28, asdescribed, for example, in DE 44 01 416 A1. A second characteristiccurve, which predefines a relationship between driving style and acorresponding desired degree of lateral support, is stored in block 29.A supplementary control variable is read out of this characteristiccurve in the block 29 by means of the classification result from block28. The supplementary control variable is fed, as an electrical signal,from the CPU 25 to the solenoid valve block 24, and sets an appropriateoutput pressure. The supplementary control variable leads to thepressure level being set in the adaptation system 18, adapted to thedriving style of the driver. The pressure level is applied in all fourair cushions 14 to 17 in the driver's seat 10 when the solenoid valveblock 24 is actuated, and results in a basic measure of lateral supportin the seat 10. After this basic pressure has been set in all aircushions 14 to 17, the solenoid valves are moved to their pressureholding position in the solenoid valve block 24 by the CPU 25.

During cornering, the control variable determined as described above isfed from the block 27 to the CPU 25. In the CPU 25, the control variableand the supplementary control variable are linked, and the electricalsignal which is fed to the solenoid valve block 25 produces, in theadaptation system 18, a compressed air setting which corresponds to thesuperimposition of the control variable and supplementary controlvariable. Depending on the direction of the current lateral accelerationb, the CPU 25 actuates the corresponding solenoid valves in the solenoidvalve block 24. As a result, the pressure in the two air cushions 14 and16 or 15 and 17, lying on the outside on the bend, of the seat part 11and the backrest 12 is adjusted to the higher air pressure, while thepressure level in the two other air cushions lying on the inside of thebend continues to correspond to the basic pressure set on the basis ofthe driving style of the driver which has been determined.

In order to compensate for the inertia which is inherent in theadaptation system 18 and to eliminate the delays between the measuringof the current lateral acceleration b and the setting of the aircushions 14 to 17, a prediction device 32 for determining in advance thevalue of the lateral acceleration to be expected on a current curve anda prediction filter 33 connected downstream of the prediction device 32are provided. The prediction filter 33 is connected at the output end ofthe control unit 19 and applies the predicted lateral accelerationvalue, supplied by the prediction device 32, to the control unit 19taking into account the filling time of the adaptation system 18. Thefilling time is a function of the filling pressure.

In a first exemplary embodiment, the prediction device 32 has a vehiclenavigation system and a digital road map which contains route datarelating to a traffic network and, if appropriate, attribute dataassigned to the route data. As an example of such a prediction device,the vehicle velocity control device described in DE 42 01 142 A1 can beused, which obtains, from the digital road map, information relating toa curve lying ahead and to its attributes, for example its radius ofcurvature. This vehicle velocity control device calculates with thevehicle data a vehicle limiting velocity with which the vehicle cantravel on the outside of the bend and can travel safely through thebend. The vehicle velocity control device can predict without difficultythe lateral acceleration which is to be expected in the bend and whichacts on the vehicle given the current vehicle velocity. The currentvehicle velocity is fed to the prediction device 32 and to theprediction filter 33 by the vehicle velocity sensor 30.

The method to be followed for the dynamic adaptation of the lateralsupport of the person seated on the front seat passenger seat will bedescribed below with reference to the example of a bend to be travelledthrough.

The expected lateral acceleration which acts on the seated person on thebend is predicted, at a relatively large distance before the bend, fromthe data which is obtained from the stored road map. The data relates tothe course of the current road and the current vehicle data which isprojected onto the course of the road. The predicted acceleration istransmitted to the control unit 19 and to the processing block 26 viathe prediction filter 33, taking into account the fillingpressure-dependent delay time of the adaptation system 18 and theinstantaneous vehicle velocity which is output by the sensor 30. At thistime, an acceleration value which has been output by the sensor 31 isstill not present at the control unit 19. As already mentioned, thepredicted value of the lateral acceleration is transformed into a sensedlateral acceleration. The degree of single-sided lateral support isdetermined in the block 27 with this sensed lateral acceleration and acorresponding control variable is transmitted to the CPU 25. The CPU 25transmits a corresponding electrical control signal to the pressureregulating device 22 which changes the filling pressure in theright-hand or left-hand air cushions 14, 16 or 15, 17 of the seatcushion 17 and backrest 12. Thus, a seat presetting is already carriedout for the lateral support when the vehicle travels into the bend, andthe lateral acceleration measured at that time by means of theacceleration sensor 31 is then used just to perform a fine correction ofthe seat presetting by minimum inflation or venting of the air cushions14 to 17.

The prediction device 32 may additionally be used to signal to thedriver in a haptic fashion that the vehicle is approaching the curveahead at too high a speed. For this purpose, the maximum value of thelateral acceleration during the curve is determined from the limitingvelocity determined in the prediction device 32 and compared with thepredicted lateral acceleration. If the predicted lateral accelerationexceeds the maximum value determined, a control signal is fed to the CPU25 via a direct control signal line 34 between the prediction device 32and the CPU 25. The control signal is converted by the CPU 25 into acontrol signal for the pressure regulating device 22, and a high fillingpressure is suddenly applied to the lateral air cushions 14 and 16 or 15and 17. The driver is warned in a haptic fashion that the vehicle isapproaching the bend too quickly. Depending on the direction ofcurvature of the bend, the air cushions 14, 16 or 15, 17, which arearranged on the side of the vehicle seat 10, lying on the outside of thebend are filled.

In a further exemplary embodiment, the prediction device 32 can also bemodified to store the seat setting or seat adaptation in the digitalroad map as a learning map. Here, for example, salient points at whichpressure changes were made in the air cushions 14 to 17 at a measuredvehicle velocity during the first journey are stored in a relationshipwith the route data as further attributes, referred to as adaptationattributes below. For this purpose, as indicated by dashed lines in FIG.1, the control signal, which is generated for the compressed airregulating device 22 by the CPU 25, is also fed to the prediction device32 so that the occurrence and the magnitude of the control signals arestored as location points for seat changes in the learning road map.When the route section is travelled along again, these adaptationattributes are used by the prediction filter 33 to determine the time ofan action by applying a predicted value of the lateral acceleration tothe block 26 of the control unit 19. In addition, it is also possible tostore the predicted lateral acceleration, as a function of the velocityand the route data, in the learning road map. When the same routesection is travelled along again, a lateral acceleration which hasalready been predicted can thus be accessed again, and only needs to beconverted with respect to the current vehicle velocity.

In an alternative embodiment of the prediction device 32 and predictionfilter 33, the prediction filter 33 is directly connected to the CPU 25by a further control signal line 35 which is indicated by dashed linesin FIG. 1. In this case, the filling pressures, which are applied to theair cushions 14 to 17 by the CPU 25 via the pressure regulating device22, are stored as a function of a velocity, for example, as a pressurechanging point or pressure level in the learning road map in arelationship with the route data. When the same route section istravelled along again, the stored pressure levels are then applieddirectly as predicted pressure levels, scaled with the current vehiclevelocity, to the CPU 25 to form the prescribed set point pressure value.The CPU 25 then itself actuates the pressure regulating device 22 inorder to set the set point pressures in the air cushions 14 to 17.

The invention is not restricted to the described exemplary embodiment ofan adaptation system 18 embodied as a pneumatic system. In theory, anyadaptation system which changes the lateral contour of the vehicle seat10 can be used. The described method is also not restricted toimplementing lateral support of the driver or further vehicle occupantsduring cornering. It is also possible to change the lumbar support orthe support of the thighs in the seat cushions as functions of theexpected course of the road section which is currently being travelledalong, for example in the road sections with severe negative or positivegradients.

1. Method for dynamic adaptation of the support of the body of a personseated on a vehicle seat, the method comprising: predicting and setting,by an adaptation system which is integrated in the vehicle seat, desiredadaptation at a point on a curved road before the vehicle arrives at thepoint taking into account current vehicle velocity from stored roaddata; actuating the adaptation system taking into account the adaptationtime inherent in the system, whereby when an event requiring theadaptation occurs, at least one adaptation presetting adapted thereto isachieved.
 2. Method according to claim 1, wherein a correction of theadaptation presetting is carried out with currently measured vehicledata during the event requiring the adaptation.
 3. Method according toclaim 1, wherein the current road course is obtained from a digital roadmap which contains route data relating to a traffic network andattribute data assigned to the route data, in that data of seatadaptations which have been carried out is stored in an assignment toroute data as adaptation attributes in the road map, and in that, whenthe route section is traveled along again, the adaptation system isactuated using the adaptation attributes.
 4. Method according to claim3, wherein a velocity-corrected adaptation measure is stored asadaptation attribute.
 5. Method according to claim 1, wherein in orderto determine the adaptation measure required when a bend is traveledthrough, the expected lateral acceleration which acts on the vehicleseat is predicted and the degree of lateral support is thus calculated.6. Method according to claim 2, wherein when the bend is being traveledthrough the lateral acceleration which really occurs is measured and thedegree of lateral support is thus corrected.
 7. Method according toclaim 3, wherein the predicted and/or measured lateral acceleration isstored as adaptation attribute.
 8. Method according to claim 5, whereinwhen the maximum value of the lateral acceleration which is derived froma predicted limiting velocity for traveling through a bend is exceededby the predicted lateral acceleration a warning signal for the driver isissued.
 9. Method according to claim 8, wherein the warning signal isfed to the driver in a haptic way by suddenly increasing the lateralsupport on the side of the seat which is on the outside in the directionof curvature of the bend.
 10. Vehicle seat comprising: a seat part, abackrest, an adaptation system for adapting body support of a personseated on the vehicle seat, the adaptation system including air cushionswhich are integrated at least in side bulges of the seat part and/orbackrest, and a compressed air regulating device for adjusting the airpressure in the air cushions, a control unit which has a controlcomputer and is connected to the compressed air regulating device andgenerates, from a lateral acceleration value fed to the control unit, acontrol signal for setting a filling pressure by the pressure regulatingdevice, a sensor connected to the control unit for measuring the vehiclevelocity, a prediction device for predicting the lateral accelerationexpected in a current curve, and a prediction filter which applies thepredicted lateral acceleration to the control unit taking into accountthe filling pressure-dependent filling times of the adaptation system.11. Vehicle seat according to claim 10, wherein the prediction devicehas a digital road map which contains route data relating to a trafficnetwork and attribute data assigned to the route data, in that timepoints of a change in filling pressure by the compressed air regulatingdevice can be stored in a relationship with the vehicle velocity and theroute data as adaptation attributes in the road map, and in that, whenthe route section is traveled along again, the prediction filter adaptsthe adaptation attributes to the current driving velocity and uses it tospecify the time when the predicted lateral acceleration is applied tothe control unit.
 12. Vehicle seat according to claim 10, wherein theprediction device has a digital road map which contains route datarelating to a traffic network and attribute data assigned to the routedata, in that filling pressures which are implemented by the compressedair regulating device can be stored, in a velocity-corrected fashion, ina relationship with the route data as adaptation attributes in the roadmap, and in that, when the route section is traveled along again, theprediction filter directly applies the adaptation attributes to thecontrol computer as set point pressure values.
 13. Vehicle seataccording to claim 10, wherein the prediction device predicts a maximumvalue of the lateral acceleration from a predicted limiting velocitywith which a current bend can be traveled through, and in that when themaximum value is exceeded by the predicted lateral acceleration, saidprediction device applies a maximum pressure value as a set pointpressure value for setting the filling pressure in the filling cushionswhich are arranged on the side of the vehicle seat located on theoutside in the direction of curvature of the bend.
 14. A method fordynamic adaptation of vehicle seat support, the method comprising:predicting a desired seat support at a point on a curved road section onthe basis of vehicle velocity from stored road data for a road which thevehicle is traveling on before the vehicle arrives at the point on thecurved road, and actuating an adaptation system to provide a seatsupport based on the predicted desired seat support when the vehiclearrives at the point on the curved road section, taking into accountdelays in the adaptation system.
 15. The method according to claim 14,wherein predicting a desired seat support includes: predicting a lateralacceleration in the curved road section on the basis of vehicle velocityfrom the stored road data; and predicting the desired seat support basedon the predicted lateral acceleration.
 16. The method according to claim15, wherein when a maximum value of the lateral acceleration for thecurved road section is exceeded by the predicted lateral acceleration awarning signal for the driver is issued.
 17. The method according toclaim 15 further comprising providing the seat support partially basedon lateral acceleration measured when the vehicle is traveling in thecurved road section.
 18. The method according to claim 14 furthercomprising storing data with the predicted desired seat support as afunction of vehicle velocity and road location along a road the vehicleis traveling on so that the stored data can be used in the future topredict desired seat support on the basis of vehicle speed and locationon the road when the vehicle travels again on the same road.
 19. Themethod according to claim 14 further comprising storing data withpressure, which is supplied to seat cushions to provide seat support, asa function of vehicle velocity and road location along a road thevehicle is traveling on so that the stored data can be used in thefuture to predict seat cushion pressure on the basis of vehicle speedand location on the road when the vehicle travels again on the sameroad.
 20. The method according to claim 14 further comprising storingdata with lateral acceleration as a function of vehicle velocity androad location along a road the vehicle is traveling on so that thestored data can be used in the future to predict lateral on the basis ofvehicle speed and location on the road when the vehicle travels again onthe same road.
 21. A vehicle seat system comprising: a vehicle seat; anadaptation system for adapting the vehicle seat for body support, theadaptation system including, air cushions which are integrated in thevehicle seat, and a compressed air regulating device for adjusting airpressure in the air cushions; a control unit including a controlcomputer, the control unit being connected to the compressed airregulating device for setting air cushion pressure; a vehicle speedsensor, the vehicle speed sensor being connected to the control unit; aprediction device that predicts lateral acceleration in a curved roadsection before the vehicle arrives at the curved road section; and aprediction filter that-sends the predicted lateral acceleration to thecontrol unit to set air cushion pressure in accordance with a desiredseat setting for the predicted lateral acceleration when the vehiclearrives at the curved road section, taking into account a delay of theadaptation system.
 22. The vehicle seat system according to claim 21,wherein the prediction device is configured to store data with aircushion pressure as a function of vehicle velocity and road locationalong a road the vehicle is traveling on so that the stored data can beused in the future to predict cushion pressure on the basis of vehiclespeed and location on the road when the vehicle travels again on thesame road.
 23. The vehicle seat system according to claim 21, whereinthe prediction device is configured to store data with lateralacceleration as a function of vehicle velocity and road location along aroad the vehicle is traveling on so that the stored data can be used inthe future to predict lateral acceleration on the basis of vehicle speedand location on the road when the vehicle travels again on the sameroad.